Which one of the following is / are incorrect ?

i) Soaps are sodium or potassium salts of higher fatty acids, such as oleic acid, stearic acid etc.

ii) Detergents are sodium salts of sulphonic acids i.e., detergents contain a sulphonic acid group, instead of a carboxylic acid group.

iii) When an oil or a fat is treated with sodium chloride solution, it gets converted to sodium salt of the acid (Soap) and glycerol.

iv) Soaps Bio-degradable where as detergents are non-bio degradable